John Deere chosen to power steel scallop trawler 'Guilding Star'

Published on: 30/10/2015

John Deere marine propulsion engines have been chosen to power ‘Guiding Star’, a 14.95m steel scallop trawler operated by marine fishing company Aquaria (Grimsay) North Uist.

Built by Macduff Shipyards Ltd, a company with over 65 years’ experience producing high quality commercial vessels up to 35m in steel, aluminum and wood, ‘Guiding Star’ is a replacement for the owner’s previous vessel and the first new boat for the Western Isles for over 5 years.

‘Guiding Stars’ main engine is a John Deere 6135AFM 85, rated 365hp (272kW) at 1800rpm arranged with heat exchanger cooling. “We modified this engine to suit the requirements of the client,” comments Sam Pearson, Sales and Technical Support Engineer for Barrus. “This included the design and production of mounting feet and a large stub shaft (FPTO), mounted on the front of the crankshaft for driving additional auxiliaries such as two large Transmotor 150amp, 24V generators, together with the pump for the Tenfjord steering gear and the fishroom refrigeration compressor,” Sam concluded.

A John Deere 6068TFM 50 engine rated 154hp (115kW) at 2300rpm is fitted on the port side for driving the hydraulics.

It was Bill Farquhar, Technical Director of Macduff Shipyards who suggested the John Deere engines for the ‘Guiding Star’ as they suited the horsepower and rpm requirement. Macduff had fitted auxiliary and generator engines previously, but this was the first John Deere propulsion engine, “The horsepower and rpm enabled us to fit a Masson NFC reverse reduction gearbox with 7.706:1 reduction ratio, driving an 1800mm diameter Kort 4 blade propeller housed in a fixed nozzle,” comments Bill.

Donald Stewart who owns Aquaria with his two brothers Hector and David comments, “The engine and the gearbox are well-matched, and there is a lot of forward thrust even at lower revs. We wanted to pull 16 heavy-duty scallop dredges with as little horsepower as possible, that’s why the model with the lowest rating was chosen. Fuel was very expensive at the time of order, especially in this part of the country. I don’t think there are many if any dredgers pulling heavy-duty gear like this with less horsepower.”

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